// Tencent is pleased to support the open source community by making RapidJSON available.
// 
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed 
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
// CONDITIONS OF ANY KIND, either express or implied. See the License for the 
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_STRINGBUFFER_H_
#define RAPIDJSON_STRINGBUFFER_H_

#include "stream.h"
#include "internal/stack.h"

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS

#include <utility> // std::move

#endif

#include "internal/stack.h"

#if defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(c++
                           98 - compat)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Represents an in-memory output stream.
/*!
    \tparam Encoding Encoding of the stream.
    \tparam Allocator type for allocating memory buffer.
    \note implements Stream concept
*/
    template<typename Encoding, typename Allocator = CrtAllocator>
    class GenericStringBuffer {
    public:
        typedef typename Encoding::Ch Ch;

        GenericStringBuffer(Allocator *allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator,
                                                                                                   capacity) {}

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS

        GenericStringBuffer(GenericStringBuffer &&rhs) : stack_(std::move(rhs.stack_)) {}

        GenericStringBuffer &operator=(GenericStringBuffer &&rhs) {
            if (&rhs != this)
                stack_ = std::move(rhs.stack_);
            return *this;
        }

#endif

        void Put(Ch c) { *stack_.template Push<Ch>() = c; }

        void PutUnsafe(Ch c) { *stack_.template PushUnsafe<Ch>() = c; }

        void Flush() {}

        void Clear() { stack_.Clear(); }

        void ShrinkToFit() {
            // Push and pop a null terminator. This is safe.
            *stack_.template Push<Ch>() = '\0';
            stack_.ShrinkToFit();
            stack_.template Pop<Ch>(1);
        }

        void Reserve(size_t count) { stack_.template Reserve<Ch>(count); }

        Ch *Push(size_t count) { return stack_.template Push<Ch>(count); }

        Ch *PushUnsafe(size_t count) { return stack_.template PushUnsafe<Ch>(count); }

        void Pop(size_t count) { stack_.template Pop<Ch>(count); }

        const Ch *GetString() const {
            // Push and pop a null terminator. This is safe.
            *stack_.template Push<Ch>() = '\0';
            stack_.template Pop<Ch>(1);

            return stack_.template Bottom<Ch>();
        }

        size_t GetSize() const { return stack_.GetSize(); }

        static const size_t kDefaultCapacity = 256;
        mutable internal::Stack <Allocator> stack_;

    private:
        // Prohibit copy constructor & assignment operator.
        GenericStringBuffer(const GenericStringBuffer &);

        GenericStringBuffer &operator=(const GenericStringBuffer &);
    };

//! String buffer with UTF8 encoding
    typedef GenericStringBuffer<UTF8<> > StringBuffer;

    template<typename Encoding, typename Allocator>
    inline void PutReserve(GenericStringBuffer<Encoding, Allocator> &stream, size_t count) {
        stream.Reserve(count);
    }

    template<typename Encoding, typename Allocator>
    inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator> &stream, typename Encoding::Ch c) {
        stream.PutUnsafe(c);
    }

//! Implement specialized version of PutN() with memset() for better performance.
    template<>
    inline void PutN(GenericStringBuffer<UTF8<> > &stream, char c, size_t n) {
        std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
    }

RAPIDJSON_NAMESPACE_END

#if defined(__clang__)
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_STRINGBUFFER_H_
